Petroleum Engineering

1. A well and reservoir have the following properties. Bo = 1.2 rb/STB pi = 4000 psia µ = 0.5 cp k = 25 md S = 0 h = 50 ft ct = 20 × 10-6 psi-1 ø= 0.2 rw = 0.3 ft, and reservoir radius, re = 5000 ft. Suppose that the well has been flowing for 10 days at 350 STB/day, calculate pressure at wellbore assuming the well is under transient flow.

2. Calculate the original oil in place in a volumetric (No aquifer connects to reservoir), undersaturated oil reservoir. Reservoir and fluid properties, and production data are given: Initial reservoir pressure, pi = 6000 psig When reservoir pressure drops to 4500 psig, Np = 1,500,000 STB Bti at 6000 psig = 1.4 rb/STB Bt at 4500 psig = 1.45 rb/STB Bw = 1.05 rb/STB Bubble point pressure, pb = 3000 psig Connate water saturation = 0.2 Water compressibility, cw = 4 × 10-6 psi-1 Formation compressibility, cf = 5 × 10-6 psi-1 Cumulative water production, Wp = 33,000 STB Cumulative water encroachment volume, We = 0 rb

3. +Ten stock tank barrels of condensate have a gravity of 55 oAPI and molecular weight of 120 lb/(lb-mole). Estimate the volume in cubic feet occupied by this condensate as a single-phase gas in a reservoir at 3000 psia and 200 oF. Gas formation volume factor at 3000 psia and 200 oF is 0.006 cu-ft/SCF. Standard condition pressure is 14.7 psia and standard condition temperature is 60 oF.

4. List two enhanced oil recovery methods that enhance oil recovery through modifying mobility ratio in the fractional flow. Explain how these enhanced oil recovery methods increase oil recovery.

5. What is the injector-producer ratio (ratio of number of injector to number of producer) for the following water flooding patterns: a. Regular four-spot pattern b. Five-spot pattern c. Inverted seven-spot pattern?

6. An undersaturated, volumetric (No aquifer connects to reservoir) reservoir has the following properties: pi = 4000 psia cw = 3 × 10-6 psi-1 pb = 2500 psia cf = 5 × 10-6 psi-1 Sw =30 percent at 4000 psia Boi =1.300 rb/STB at 4000 psia ø=10 percent at 4000 psia Bo =1.320 rb/STB at 3000 psia A= 60 acres h = 50 ft Wp = 0 STB Bw =1.05 rb/STB Calculate the stock tank oil in place at 4000 psia and at 3000 psia, and then calculate the recovery factor at 3000 psia.

Petroleum Engineering 1. A well and reservoir have the follow...